Mothers’ smoking during pregnancy probably does not lead to substance abuse in their children, as earlier studies suggested, according to researchers at Indiana University. Previous research indicated that mothers’ smoking in pregnancy leads to a greater risk of substance abuse in their children, according to MedPageToday.

The new study suggests any link between mothers’ smoking and children’s substance abuse is likely due to family background. The researchers note siblings have similar rates of substance abuse regardless of their specific exposure to their mother’s smoking.

Brian D’Onofrio, PhD reports in the Archives of General Psychiatry that when mothers changed their smoking habits during different pregnancies, there was no change in substance abuse risk in their children.